Method of producing a predetermined color effect in concrete and stucco



J. J. EARLY.

METHOD OF PRODUCING A PREDETERMINEO COLOR EFFECT IN CONCRETE AND STUCCO. APPucATloN FILED JULY e, 1920.

1 ,376,'?48. htented May 3, 192L UNITED STATES PATENT OFFICE.

JOHN J. EARIiEY, OF WASHINGTON, DISTRICT OF COLUMBIA.

METHOD OF PRODUCING A PREDETERMINED COLOR EFFECT IN .CONCRETE AND STUCCO.

Application filed July 6,

'To all whom it may concern:

Be it known that I, JOHN J. EARLEY, a

citizen of the United States, and a resident of lVashington, in the District of Columbia, have invented certain new and useful Im'- provements in Methods of Producing a Predetermined yColor Effect in Concrete and Stucco, o f which the following is a specification. f Y

This invention relates to a method of treat-ment of structural surfaces which is broadly'known as stucco. This improved method is also applicable to the formation of concrete floors, ornamental urns, pillars, arches, balustrades, building details, etc., and by this method, a greater variety of color and texture schemes may be had, than with any known process now in use.

Broadly,'the object of this invention is to reproduce in concrete a surface colored after the impressionistic school.

Another object is to so 'control the amount of large aggregate and cementing material that the desired true color will result with the minimum amount of interference of false tints.

Still another object of this invention is to obtain the desired texture on the finished product by the grading of the aggregate.

Still another object is to devise a method of stuccoing which will be uniform at all times. This, heretofore has been purely a matter of guess work and depending on skill alone to match the color and texture of the former work.

ln the figure A is a graphic illustration of concrete made after this method.

B is a graphic illustration of concrete made after the ordinary method.

The major difference between the appearance of stucco and concrete treated by my process and that of stucco and concrete not so treated lies in the gradation of the aggregate. Other operators and investigators 'have studied the gradation of aggregate and the laboratories and the profession have accepted the definition of a well graded aggregate to be one in which the particles are evenly divided both as to size and number running from fine to coarse. A graphic illustration is given in the accompanying diagram, of the ordinary method as graph B. An aggregate, according to this principle, is well graded or not in just such a degree as the curve of its granular analysis Specification of Letters Patent.

ratentedara'y 3, 1921.

1920. Serial No. 394,104.

on this diagram conforms to or differs from the ideal diagonal straight line'. Thetype of gradation is called a straight line gradation because its ideal finds expression in .suchl a li'ne on this diagram. The characteristics of materials graded on this principle or any approximation of it, are not suitable to the expression of form, color and texture 1n the materials and for the purposes under consideration. My investigation has led-'to the discovery that the proper gradation of aggregate for the particular use, is one in which the aggregates are divided into groups, the particles of which are all of about one size and recombined-With a definite ratio of size of the grains and the vvolume of each size.

Graph A shows a Vdiagram expressing my lmproved method of grading as opposed to the one mentioned above. This type of grading is called step gradation.

Stucco or concrete prepared by my process differs from the usual stucco or concrete in that it has in an artistic and anarchitectural sense, better form, color and texture. f

It has better form because under this method it can be successfully molded intoV more complicated shapes than the ordinary material and therefore it is better able to express architectural and artistic design.

It has better-color and texture because it receives its color and texture from the large aggregate, which is an element which may be carefully selected for color and carefully graded t0 a definite size of grain for texture.

The ordinary material derives its color mainly from the cementing materials and the finest of its ingredients, and as the cementing material is a false color, the true color of the whole will be'limited by the extent of the interference of the cementing material. Stucco or concrete prepared d,by my method derives its color mainlylfrom the coarsest of its materials, the finest of which may be also carefully selected as to color, in order to reduce the interference of the cementing material to a minimum.,y

In ordinary material the textureis lar ely a function of the character of the combined materials, while in this process it is largely due to the character of the coarse material or the large aggregate. Thus, by controlling the dimensions and number of thelarge aggregate, the desired texture will be obtained.

The selection of large aggregate to obtain the desired color and texture is a matter of personal taste and judgment and in, is found the expression of artistic ability, which is a personality and therefore artistic, architectural and manipulative skill is necessary to obtain the maximum amount of success, `which is not possible without grading by the above method.

In the process herein described, great care must be exercised so that the particles of each group of aggregate will take their place in the mass in' such a way that when the surface treatment is applied they will be where they were designed to be. This part of the process is one of -careful supervision and fine workmanship based upon experience with 4materials having the characteristics vwhich this step gradation gives, not otherwise possible.

Having 4now described the selection of the large aggregate which is the factor upon which the color and texture of the work depends, we now take up the two other elements, namely cementing material and water.

Any suitable brand of Portland cement may be used in a proportion which is sufficient to produce concrete of the required strength, but not so much as` willf disturb the chai'acter of the aggregate by over filling the voids therebetween. If this is done, both the color and texture schemes may be disturbed to such an extent' as to be en. p tirel lost. l'atei' must be added of a sufficient quantity to hydrate the cement and to form a .mass of the proper consistency or How to permit it to be worked. This proportion naturally varies with the character of the work. For instance, if the work is to be of a molded nature, the consistency should be at- .tained by the addition of the least amount of water which will give to the mass of concrete a property by which it can be made to flow into the int'eistices of the mold which it is to fill. In the case of stucco work the consistency or iiow should be attained by the addition of the greatest amount of water that will not cause slip or segregation. The other two factors remain the same in both cases.

It is impossible to state definitely a quantity of each ingredient as the proportions vary greatly and experience is the factor which will decide in all cases.

In the case of molded work, the mass of concrete is packed carefullyfinto any suitable mold of a waterproof construction, so that each part of the mold comes in contact with the mass. In stucco work, the 4mass is applied with a trowel to any of the approved building structures such as brick, stone work, metal lath, etc.

.In both of the above cases, upon hardening it will be found that a greater concentration of small aggregate and cemeiiting material will appear at the surface of the mold or the exterior of the stucco work. The larger aggregate will be found to lie in substantially a plane surface about beneath the surface and may be exposed by brushing away the surface with a wire brush. If desired the exposed surface of large aggregate may be treated with a weak acid to better bring out the natural color of the same.

When the surface is thus exposed, it will be found that the groups of aggregates selected will lie in such a definite relation to .mined color effect in concrete which includes the steps of rading `aggregate into a definite grade of size and color, commingling said grade of aggregate with cementing material and water, molding or applying the resultant mixture, and treating the surfaces of the work so that said aggregate protrudes from said surface.

2. A method of producing a predetermined color effectl in concrete which includes the steps of grading aggregate into definite groups of size and color, commingling said aggregates with ceinenting inatei'ial and water and molding or applying the resultant mass, said groups being widely separated as to size, the particles of the smaller group arranging themselves between particles of the next larger group so' as to reduce the visual color effect of the cementing material to a minimum and treating the surface of the work so that said aggregatey protrudes from said surface.

In testimony whereof I affix my signature.

JOHN J. EARLEY. 

